things growing in my tank, not good?

[areefdream]

Hello, hello,
Ever since I moved to the Kootenays I have found small changes with my tank, and I am not sure if they are good. I have addopted a large amount of pests, (they look like miniature brittle star fish that love hiding in my coral and live rock especially. They don't seem to bother too much but myself. What are they? Are they harful? How do I get rid of them if they are? Also I have a considerable more green vegetation growing in my tank at the moment. I am still new to the hobby and have a small tank (33g) and find that if not nippeed in the butt problems spread fast. I appreciate the insight. Thank you
Trevor